Removable deep tank gas diffusing apparatus

ABSTRACT

An apparatus for diffusing gas in tanks containing liquid mediums that is elevatable out of the tank for servicing which comprises a guide member supported from the tank top and extending downwardly to a point in the vicinity of the bottom of the tank, a traveler support member associated with said guide member, a gas diffuser header secured to said traveler support member, means for actuating said traveler for upward and downward movement, at least one stationary gas duct connected to a gas supply line and extending vertically downwardly to a point in the vicinity of the tank bottom, a first air pipe pivotally secured to the lower end of said stationary gas duct, a second air pipe pivotally secured at its other end to said gas diffuser header, a plurality of diffusers secured to the tubular header and spaced supports in contact with the tank bottom and the header when said header is in its lowermost position.

United States Patent 1 Nechine [54] REMOVABLE DEEP TANK GAS DIFFUSING APPARATUS [75] Inventor: Leonard M. Nechine, Highland Park Ill.

[73] Assignee: FMC Corporation, Chicago, Ill. [22] Filed: Feb. 22, 1971 [21] Appl. No.: 117,567

[52] U.S.Cl. 261/122 [51] Int. Cl ..B01f3/04 58 Field ofSearch 261/122, 124, me. 47;

[111 3,738,628 June 12, 1973 Primary Examiner-Frank W. Lutter Assistant Examiner-Robert Halper Attorney-Dressler, Goldsmith, Clement & Gordon 57] ABSTRACT An apparatus for diffusing gas in tanks containing liquid mediums that is elevatable out of the tank for servicing which comprises a guide member supported from the tank top and extending downwardly to a point in the vicinityof the bottom of the tank, a traveler support member associated with said guide member, a gas diffuser header secured to said traveler support member, means for actuating said traveler for upward and downward movement, at least one stationary gas duct connected to a gas supply line and extending vertically downwardly to a point in the vicinity of the tank bottom, a first air pipe pivotally secured to the lower end of said stationary gas duct, a second air pipe pivotally secured at its other end to said gas diffuser header, a plurality of diffusers secured to the tubular header and spaced supports in contact with the tank bottom and the header when said header is in its lowermost position.

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ATTORNEYS REMOVABLE DEEP TANK GAS DIFFUSING APPARATUS This invention relates to systems for the gasification of liquids. More particularly, it relates to sewage treatment systems with piping and linkage arrangements for rendering diffuser apparatus readily insertable into and retractable from sewage aeration tanks. Still more particularly, it relates to gas diffusion apparatus for use in deep tanks by means of which a header designed for deep submergence and having a plurality of gas diffusers attached thereto is provided with linkage arrangement for conducting gas to the diffusers and an actuatable support means for raising the header out of the tank for servicing.

Briefly, the apparatus for diffusing gas in tanks containing liquid mediums of this invention comprises guide means adapted to support a diffuser assembly for rectilinear movement mounted in said tank and extending downwardly to a point in the vicinity of the bottom thereof, a traveler support member movable along said guide means for elevating said gas diffusing apparatus to a point above the liquid level of said tank for servicing, means for actuating said transfer member for upward and downward movement, a gas diffuser header secured to said traveler support member in a generally horizontal position in a plane parallel to said wall having an operating and servicing position, a gas supply line mounted adjacent the top of the wall of said tank which supports said guide member, piping means having sections thereof movable in cooperation with said header connecting said gas diffuser header to said gas supply line, a plurality of diffusers secured to said gas diffuser header and spaced supports in contact with the tank bottom and said gas diffuser header when said header is in its lowermost position.

Systems for gasifying liquids such as aqueous mediums, sewage and industrial wastes, customarily involve tanks holding appreciable volumes of liquid and extensive gas piping installations with elaborate associated mechanisms for breaking up the gas streams into relatively small bubble form.

Systems, for example, for treating sewage have aerators disposed inside the tanks and submerged well below the normal liquid level in the tank. Such aerators tend over a period of time to accumulate solids matter which interferes with gas dispersion. Operating difficulties have made it necessary to design equipment which can be readily serviced. In order to facilitate servicing without having to dewater the tank, gas dispersion units have been suspended in a manner permitting the units to be raised above the liquid level by swinging the units upwardly out of the tank as illustrated in Chase U.S. Pat. No. 3,174,733 and Walker U.S. Pat. No. 3,339,901.

Diffuser headers in use heretofore supported by lift apparatus of the so-called swing type have been limited as to a length and have been characterized by air pipes providing at least part of the mechanical support through pivotal connections between the header units and hanger pipes and between the hanger pipes and the stationary header from which the swing is supported.

In shallow tanks, raising such headers and associated diffusers, for example, by means of a hoist arranged to act at some point on the upper hanger pipe, had presented only minor problems such as are encountered when machine surfaces have become non-movable due to corrosion.

As the volume of sewage flowing to established sewage treatment plants has increased and the requirements for the degree of treatment have been raised, increases in the capacity of treatment tanks have been required. Since the treatment plants in many areas have little space available for expansion, the increased requirements have had to be met by substantial increases in tank depth.

Raising long headers and associated diffusers out of deep tanks presents serious problems. The cantilever effect of the weight of large headers and banks of dispersers plus the liquor which fills them when the air is shut off is often too great for the strength of the construction materials and the overstress results in breakdowns at the points where pivotal connections are made to stationary piping.

Now it has been discovered that long headers and associated gas dispersers can be provided with means for moving them out of a tank for servicing which does not involve use of air supply lines as structural support members and overcomes the cantilever effect of headers and dispersers and water in them when air is shut off which has heretofore been too great for the strength of the construction materials.

An assembly for raising and lowering headers and associated gas diffusers in tanks containing liquid mediums, of the present invention, comprises a guide member supported from the top of the tank and extending downwardly in the tank to a point in the vicinity of the bottom thereof, a traveler support member associated with said guide member, means for actuating said traveler support member for upward and downward movement, a gas diffuser header secured to said traveler support member, at least one and preferably a pair of stationary gas ducts spaced so that said guide member is in an intermediate position, connected to a gas supply header, which stationary gas ducts extend vertically and provides an outlet in the vicinity of the tank bottom, a first air pipe pivotally secured to the outlet end of said stationary gas duct, a second air pipe pivotally secured at one end to said first air pipe and pivotally secured at its other end to said gas diffuser header, a plurality of diffusers secured to the tubular header and spaced header supports in contact with the header and the tank bottom to establish horizontal positioning when the header is in its lowermost operating position.

More in detail, in the preferred embodiment of the assembly, the apparatus comprises a guide member which is a hollow tubular member, preferably of square cross-sectional configuration, which has a stationary support mounted on top of the tank wall and. extends downwardly parallel to and in a position spaced a short distance from the tank wall. The tubular member is provided with a longitudinal slot in the side parallel to and removed from the tank wall.

A traveler support member is positioned inside said tubular member and is provided with guide wheels which contact the interior. of said tubular guide member. The traveler support member is also provided with two vertically spaced chain sprockets which cooperate with a chain actuator to move the traveler support member upwardly or downwardly. At the top. and bottom of the guide, means is provided for locking the header in the operating or maintenance positions. The chain actuating means is driven by a suitable source of power such as an electric motor through a gear reduction unit the output shaft of which has a sprocket wheel mounted thereon. The chain actuating means may be an endless drive chain with the traveler attached at one or more point thereof.

An alternative apparatus for raising and lowering the header may consist of a traveler support mounted on a translation device adapted to convert rotary motion to linear motion and causes movement raising or lowering the traveler depending upon the direction of rotation of the vertical externally threaded shaft. Such a translation device is adapted with suitable bearings mounted in housings secured to the bottom and to the top of a wall of a tank.

The traveler support member is provided with a connector which extends through the slot in said tubular guide member. The connector is attached by suitable means to the gas diffuser header, preferably at a central location so that the sections of the horizontal header extending therefrom will provide balancing weights.

In order to provide uniform distribution of gas, the header must be in a substantially horizontal position when at its lowermost, i.e., operating, position. To insure such positioning, adjustable header supports of appropriate length are provided which may be in the form of downwardly extending arms attached to the header or take the form of saddles affixed to supports mounted on the bottom of the tank, the supports having a length such that a pipe resting in a plurality of saddles will be in a substantially horizontal position. Such supports also serve a second purpose of pre-stressing the header and eliminating vibratory effects usually associated with the discharge of gas from the diffusers.

Discharge of gas may be from diffusers of varying sizes and types which may be positioned on one or both sides of the gas diffuser header. Connection of the header to a suitable source of gas or air under pressure is preferably obtained through segmented connectors, the first segment of which is a stationary gas duct which is a branch pipe from a main conduit generally positioned either in a Y section at the top of a vertical wall of the tank or beneath an overhang of the walkway in a T-configuration wall. Each stationary duct is provided with a gas control valve. The outlet end of each stationary duct has a first air pipe pivotally connected thereto. The pivotal connection is mounted so that direction of movement of the air pipe will be in a plane parallel to the tank wall. A second air pipe is pivotally secured at one end to the first air pipe and at its other to the header. The pivotal connections for the second air pipe are mounted so that the direction of movement is in a plane parallel to the plane in which the first air pipe moves'during lifting or lowering of the header. In order to maintain the header in a reasonably level position during raising and lowering, torque springs may be incorporated in the knee joints connecting said first and second air pipes.

The structure by means of which the abovementioned and other advantages are attained, is described in detail in the following specification, taken in conjunction with the accompanying drawings, showing the preferred illustrative embodiment of the invention, in which:

FIG. 1 is a perspective view showing the header in a position slightly above the operating position in the tank;

FIG. 2 is a perspective view of the apparatus when the header is in its servicing position above the tank;

FIG. 3 is a fragmentary end view of the header lift mechanism showing the header in its operating position;

FIG. 4 is a fragmentary front view of the header lift apparatus;

FIG. 5 is a fragmentary top plan view of the header lift mechanism showing the actuating means for the lift:

FIG. 6 is a fragmentary end view showing the service module having a lower platform section extended over the area of the tank below the dispersers and header which have been moved to their uppermost position for servicing and an upper arm section in contact with the header;

FIG. 7a is a side elevational view showing the means for support of the header to lock it in position during servicing; and

FIG. 7b is a top plan view of the support for locking the header in the servicing position when pivoted to the side so as to allow vertical movement of the header.

In the drawings, FIGS. 1 through 4, the reference numeral 10 indicates a sewage tank having a vertical wall 11 offset adjacent the top to provide space for an air main 12. An air feed fitting 13 extends outward of the coping and connects the air main 12 to a vertical air duct 14. A suitable valve (not shown) is positioned in the line adjacent to air feed fitting 13 to control the flow of air from the air main 12. A second air feed fitting 15, spaced from said air feed line 13, extends outward of the coping and connects the air main 12 to a second vertical air duct 16.

Stationary vertical air ducts 14 and 16 are provided at their lower ends with base elbows l7 and 18 whose vertical flanges are positioned in a plane parallel to the wall 11. Elbows l7 and 18 are provided with extensions 19 and 20. Extensions 19 and 20 have terminal flanges disposed in vertical planes.

Elbows 21 and 22 are aligned with the extensions of elbows 17 and 18, respectively, and are pivotally secured to the extensions by means of studs 23 and 24 disposed centrally of the elbows. The open ends of the elbows 21 and 22 are of the same size as the circular openings at the ends of extensions 19 and 20 with which they are in registration. A seal 25 is interposed between the extension 19 and elbow 21. A similar seal is interposed between the extension 20 and the elbow 22. The seal permits pivotal movement of the elbows relative to the stationary horizontal extensions of the elbows 17 and 18 and prevents leakage of air at the joint.

The elbows 21 and 22 have an upper and lower open end disposed in perpendicular planes. It will be understood that the designations upper and lower are used throughout the specification and claims to indicate the relative positions of the parts when the assembly is in the servicing position as indicated in FIG. 2.

A lower movable pipe section 26 has its lower end rigidly secured to the upper open end of elbow 21. A similar movable pipe section 27 of length identical with section 26 has the lower end rigidly secured to the upper open end of elbow 22. The upper end of movable pipe section 26 is rigidly secured to the lower open end of. a knee 28. The upper open end of knee 28 is disposed in a plane parallel to the plane in which the lower open end of elbow 21 is disposed. The knee 28 has its lower open end in a plane parallel to the plane in which the upper open end of elbow 21 is disposed.

The upper open end of knee 28 is in registration with a vertical opening of the same size at the lower end of an upper knee 29. The upper and lower knees are pivotally secured together by a stud 30 disposed centrally of the vertical openings and extending parallel to the stud 23. A seal 31, similar to seal 25, is interposed be tween the upper open end of knee 28 and the lower open end of upper knee 29.

The upper knee 29 has an upper open end which is disposed upwardly and has the lower end of an upper pipe section 32 rigidly secured thereto. The other open end of pipe section 32 is rigidly secured to the lower open end of an elbow 33. Elbow 33 has an upper open end disposed in a vertical plane perpendicular to the plane of the lower open end of the elbow and parallel to the plane of the lower open end of knee 29. The upper open end of elbow 33 is of the same size and is adapted to cooperate with a vertical flange 34 of an elbow 35. Elbow 35 has an upper horizontal flange 36 secured to the horizontal flange 37 of the hollow nipple 38 or joint extending downwardly from diffuser'header 39 and communicating with the interior thereof and se cured to the header as by welding. Elbow 33 is aligned with the aperture in the elbow 35 and is pivotally secured thereto. A seal 40 is interposed between the elbow 35 and the elbow 33.

The diffuser header 39 comprises two sections 41 and 42 for attachment of diffusers 43 thereto and a coupling section 44 which serves to provide communication for gas between header sections 41 and 42 so that the gas pressure exerted on all of the dispersers will be substantially the same. Diffuser header sections 41 and 42 have a plurality of threaded openings 45 into each of which a diffuser tube 43 is screwed.

Coupling section 44 of header 39 is secured by a plurality of U-shaped bars 45 to a header lift apparatus 46.

The header lift apparatus 46 comprises a tubular member 47 suspended by support arms 48 mounted on plate 49 which is rigidly secured to the top of wall 11 by anchor bolts 50. Tubular member 47 is provided with a semicircular shaped bottom member 51 having an external projection 52. Projection 52 is adapted with a threaded recess 53 to receive the threaded stem of an eye member 54. Eye member 54 is hooked to one end of a tension spring 55 which will provide compensation for temperature changes and structural variations. The other end of spring 55 is hooked to an eye member 56 mounted in adjustable length position in a base member 57 secured to the floor of tank 10 by suitable means 58, such as anchor bolts. Base member 57 is intermediate spaced members 59 for support of the header 39 when the header is in the operating position.

Bottom member 51 is adapted with parallel sides 60 and 61 which provide a base for journals 62 and 63, respectively. A shaft 64 is mounted in the journals 62 and 63. Sprocket wheel 65 is mounted on shaft 64.

Tubular member 47 is provided with a top closure member 66 adapted with sides 66a and 66b which provide a base for journals 68 and 69, respectively. A shaft 70 is mounted in the journals 68 and 69. A sprocket wheel 71 is mounted on shaft 70 inside the top closure member 66. A sprocket wheel 72 is mounted on shaft 70 externally of side 66a of top closure member 66. A sprocket support casing 73 is secured to the side 66a so as to enclose the sprocket wheel 72. Casing 73 extends downwardly toward the top of wall 11 and is anchored at its lower end to an angle bracket 74 mounted on the top of said wall. Casing 73 is provided with plates 73a and 73b. A shaft 75 is journaled in plates 73a and 73b. A sprocket wheel 76 of diameter markedly less than sprocket wheel 72 is mounted inside the casing 73 on the shaft 75. A drive chain 77 is trained over the sprockets 72 and 76. Shaft 75 is adapted on the side adjacent plate 73b with a coupling 75a adapted to be connected with the output shaft of a motorized gear reduction unit 78 removably mounted on the base portion of angle bracket 74, for example, actuation being by an electric motor. If an electric motor is the actuation means for unit 78, the motor may be of the reversing type whose rotation in each direction can be controlled by limit switches.

An endless pintle chain 80 is trained over sprocket wheels 65 and 71.

- fixed path. Legs 83 and 84 and a projection 85 are provided with spaced connections to chain 80 by pintle links 86a, 86b and 86c. Traveler member 82 is also provided with arm members 87 and 88 which extend through the slot 81. Arm members 87 and 88 have a plate 89 affixed thereto. Plate 89 has holes 90 therein. The threaded terminal ends of U-bars 45 which encircle the coupling section 44 of header 39 pass through plate 89 and are locked in place by nuts 91.

Referring to FIGS. 2 and 6, there is illustrated a service module 92 which is partially supported by the header when the header is in its servicing position and supports a work platform which extends from the tank coping to a point below the header.

Service module 92 has as basic frame members a pair ofparallel spaced structural supports 93 and 94 which are of circular cross-sectional configuration and in a side elevational view have a U-shape with the open end directed toward the interior of the tank. The lower horizontal leg of supports 93 and 94 each have duplicate casters depending therefrom, adjacent the closed ends 93a and 94a. As illustrated in FIG. 6, caster 96 has a V-grooved wheel 98.

Wheels of the casters are mounted in alignment for travel on a coping track 100 mounted on an angle iron 101 secured by suitable anchor bolts to the top of the coping of wall 11. Angle iron 101 has the leg 102 positioned vertically to act as a safety guard.

Structural supports 93 and 94 are secured as by welding in the areas adjacent said casters to a U-shaped brace 103 having the legs thereof positioned vertically and the ends of the vertical legs rigidly secured, as by welding, to the top horizontal legs of said supports 93 and 94. Brace 103 is positioned relative to the closed end of the structural supports so that the vertical legs will be spaced from the ends of the gas diffusers 43 wich extend from header 39 in the direction of the tank wall 11. Stiffener pipe means 104 and 105 have the end of its lower leg rigidly secured to the end of the lower leg of structural supports 93 and 94, respectively. The stiffener pipe means have sections 104a and 105a which extend parallel to the lower horizontal legs of supports 93 and 94, a U-shaped section 104b and 105b, the vertex of which extends into contact with closed ends 93a and 94a of supports 93 and 94 and an upper leg section 1040 and 1050 which is spaced from and parallel to the upper leg of supports 93 and 94, respectively. Stiffener pipe means 104 and 105 are locked to support means 93 and 94, respectively, by braces 106, 107 and 108.

The ends of the upper leg of support 93 and of the upper leg section 1040 of stiffener pipe 104 are secured by suitable means, such as set screws to a casting 110. Casting .110 is adapted with a hollow lower section 111 having a horizontal bottom wall 111a and connecting angled walls lllb and lllc. Walls 111b and 1110 support journals for shafts 112 and 113 which in turn have guide wheels 114 and 115 mounted thereon.

A casting 116, identical to casting 110, is supported at the ends of support 94 and stiffener pipe 105. A cross bar 117 extends between the castings 110 and 116 to insure maintenance of a fixed spacing.

A floor member 118 extends between and is secured to the lower horizontal legs of supports 93 and 94 by suitable means 119, such as set screws.

Referring to FIGS. 7a and 7b, there is illustrated a stabilizer member 120 which is mounted on the coping of wall 11 for support of the header 39 when the header has been raised to its servicing position. Two stabilizer members 120 are mounted on the coping of wall 11 in positions adjacent the opposite ends of header 39. Stabilizer member 120 consists of a base plate 121 positioned adjacent to and parallel to the vertical surface of the coping for sliding engagement therewith. Base plate 121 has secured thereto to the upper portion thereof an angle iron member 122 and has secured to the lower portion thereof a straight arm l23-extending upwardly at about a 45 angle, the arm and angle iron members being aligned in a plane vertical to said plate. Angle iron 122 and straight arm 123 are secured together by suitable means such as welding to form a cradle for header 39. Plate 121 is suspended in a rotatable position by being secured in a central portion to a crank 124. Crank 124 is pivotably mounted in a sleeve support member 125 extending horizontally along the top of the coping of wall 11.

FIG. 3 illustrates the position of the header and air diffuser means when it is in operation in a tank. The air under relatively low pressure is released into the liquid in the tank through diffusers 43. When the header and diffusers are in the operating position, locking means prevent the assembly from being raised by the buoyancy of the liquid in which it is immersed because the traveler member 82 can only rise when the chain 80 is free to travel. Movement of the chain 80 is restricted by the gear ratio in the gear reduction box coupled with the reduction in speed effected by the ratio of diameters of sprocket wheels 71, 72 and 76. Generally, the header movement is limited to movement at a rate of feet per minute. When the header is lowered to its operating position, it rests on supports 59 positioned approximately midway of the length of header sections which support diffusers. Supports 59 can be of a type anchored to the tank bottom or may be support legs threaded into sockets depending from the underside of the header sections. Such threaded supports provide means for adjusting the legs so that they can be set to bear against the floor of the tank with such force that the buoyancy of the header and upward forces due to upward flow of fluid on the tank cannot raise the lower end of the leg from its bearing upon the tank floor.

The lift apparatus in moving from between the lowermost position and the uppermost position shown in FIG. 2 causes the knee joints 28 and 29 connecting the air pipes 26 and 32 to travel through an arc of The air pipes and header will be in parallel horizontal positions only when the header is at the operating position at the bottom of the tank.

While a preferred embodiment of the invention has been described in considerable detail, it will be understood that the description thereof is intended to be illustrative, rather than restrictive.

I claim:

1. Apparatus for diffusing gas in the liquid medium contained in a tank having a vertical wall, said apparatus being elevatable out of the tank for servicing which comprises guide means supported by said vertical wall for vertical rectilinear movement of a diffuser assembly mounted within said tank and extending downwardly in said tank to a location in the vicinity of the bottom thereof in a vertical plane spaced from said vertical wall, said guide means being located at a central location of said diffuser assembly, a traveler support member movable along said guide means, means for actuating said traveler support member for vertical movement, a gas diffuser header having an operating and servicing position secured to said traveler support member in a generally horizontal position in a plane parallel to said vertical wall, a gas supply line mounted adjacent the top of said vertical wall, piping means having sections movable in cooperation with said gas diffuser header connecting said header to said gas supply line and consisting of one or more stationary gas ducts connected to said gas supply line and extending downwardly along said vertical tank wall to a location adjacent the bottom of said tank, a lower section of gas pipe pivotably secured at one end of the lower end of said stationary gas duct and adapted to move in a plane parallel to said vertical wall, an upper section of gas pipe connected at one end by a knee joint to said lower section of gas pipe and at its other end to said gas header, a plurality of diffusers secured to said gas diffuser header, and spaced supports in contact with the tank bottom and said gas diffuser header when said header is in its lowermost position.

2. Apparatus according to claim 1 in which the gas diffuser header when in said servicing position is one of the support members for a service module, another support of which is a caster cooperating with a track mounted on the top of said vertical wall, said module providing a support base for a platform extending outwardly from the tank wall to an area below said header. t 0 I ll 

1. Apparatus for diffusing gas in the liquid medium contained in a tank having a vertical wall, said apparatus being elevatable out of the tank for servicing which comprises guide means supported by said vertical wall for vertical rectilinear movement of a diffuser assembly mounted within said tank and extending downwardly in said tank to a location in the vicinity of the bottom thereof in a vertical plane spaced from said vertical wall, said guide means being located at a central location of said diffuser assembly, a traveler support member movable along said guide means, means for actuating said traveler support member for vertical movement, a gas diffuser header having an operating and servicing position secured to said traveler support member in a generally horizontal position in a plane parallel to said vertical wall, a gas supply line mounted adjacent the top of said vertical wall, piping means having sections movable in cooperation with said gas diffuser header connecting said header to said gas supply line and consisting of one or more stationary gas ducts connected to said gas supply line and extending downwardly along said vertical tank wall to a location adjacent the bottom of said tank, a lower section of gas pipe pivotably secured at one end of the lower end of said stationary gas duct and adapted to move in a plane parallel to said vertical wall, an upper section of gas pipe connected at one end by a knee joint to said lower section of gas pipe and at its other end to said gas header, a plurality of diffusers secured to said gas diffuser header, and spaced supports in contact with the tank bottom and said gas diffuser header when said header is in its lowermost position.
 2. Apparatus according to claim 1 in which the gas diffuser header when in said servicing position is one of the support members for a service module, another support of which is a caster cooperating with a track mounted on the top of said vertical wall, said module providing a support base for a platform extending outwardly from the tank wall to an area below said header. 